node-rate-limiter

Simple calls rate limiter for Node.js®, inspired by @tj's node-ratelimiter

Package contains NodeRateLimiter that uses different adaptors for store rate's data to varios stores. By default NodeRateLimiter supports local process memory, but you can also use following adaptors:

• node-rate-limiter-redis - adaptor for Redis database

Install

npm install node-rate-limiter

Usage

You can find default values under NodeRateLimiter namespace

  NodeRateLimiter.defaults = {
    rateLimit: 5000,      // default number of call for current timeframe
    expiration: 3600000,  // default duration in ms of current timeframe
    timeout: 500          // default timeout in ms of reset/get methods call
  };

You can use default in memory store of current process just providing empty adaptor

const NodeRateLimiter = require('node-rate-limiter');
const nodeRateLimiter = new NodeRateLimiter();

Or You can use one of the existing providers

const NodeRateLimiter = require('node-rate-limiter');
const SomeAdaptor = require('some-adaptor-package');

const nodeRateLimiter = new NodeRateLimiter(new SomeAdaptor({/*...*/}));

You can wrap your internal system module method

function someInternalSystemModuleMethod(clientId, arg1, /*...*/ argN, callback) {
  nodeRateLimiter.get(clientId, (err, limit) => {
      if (err) {
        throw err;
      }

      if (!limit.remaining) {
        return callback(new NodeRateLimiter.RateLimitError(limit));
      }

      someInternalSystemModule.someMethod(arg1, /*...*/ argN, callback);
  });
}

Or use it like middleware f.ex in Express

const NodeRateLimiter = require('node-rate-limiter');
const SomeAdaptor = require('some-adaptor-package');

const nodeRateLimiter = new NodeRateLimiter(new SomeAdaptor({/*...*/}));

const express = require('express');
const app = express();

app.use('/api', RequestRateLimitMiddleware);
app.get('/api/integers/:a/add/:b', (req, res) => res.send(parseInt(req.params.a) + parseInt(req.params.b)));
app.get('/api/integers/:a/sub/:b', (req, res) => res.send(parseInt(req.params.a) - parseInt(req.params.b)));

app.listen(3000, function () {
  console.log('Example app listening on port 3000!')
});


function RequestRateLimitMiddleware(req, res, next) {
  nodeRateLimiter.get(res.yourUniqIdForCurrentSession, (err, limit) => {
    if (err) {
      return next(err);
    }

    res.set('X-RateLimit-Limit', limit.total);
    res.set('X-RateLimit-Remaining', limit.remaining);
    res.set('X-RateLimit-Reset', limit.reset);

    if (limit.remaining) {
      return next();
    }

    res.set('Retry-After', limit.reset);
    res.send(429, `Rate limit exceeded, retry in ${limit.reset} ms`);
  });
}

If method call least too long, then callback will fires with Timeout error.

  nodeRateLimiter.get(someId, (err, limit) => {
    if (err && err.name = 'TimeoutError') {
      /* handle timeout error */
      return;
    }

    /* ... */
  });

License

MIT